The New England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (NERCE) has now been active for over five years. NERCE originally set several goals that have been achieved to a significant degree. These goals were to translate existing scientific information into deployable technology, to bring the scientific creativity of our community to bear on developing novel approaches to treatment and prevention of infections, and to provide training opportunities for scientists and physicians in biodefense and emerging infectious diseases. We wanted to create a center that served as a focal point for research and development in biodefense and emerging infectious diseases to be utilized by scientists from academia, the public health sector, and the pharmaceutical and biotechnology industries. Our intent was that this center would function as a catalyst for basic, translational, and clinical research scientists to conduct research leading to new products directed against infectious agents. Statistics from the first five years provide evidence of our success in achieving these goals. We have funded 65 investigators from 15 institutions throughout New England, most of whom had no prior experience working with biodefense pathogens. Fourteen patents have been filed and 101 manuscripts published as a result of support provided by NERCE. In addition, a major function of NERCE has been to establish core facilities to enable research for investigators throughout the region (including those not directly funded by NERCE) whose base institutions cannot provide the required infrastructure to work with these pathogens. Our core laboratories have been utilized by 150 scientists, not only from our region but also from nearly every other RCE in the US. Our National Small Molecule Screening Core (NSRB) has collaborated with over 70 investigators (half from outside our region) in conducting high-throughput small molecule screens for compounds that inhibit specific molecules or biological pathways of interest. The NSRB has been the most successful of the transcenter core laboratories supported by the RCE program. We have developed extensive synthetic and natural compound libraries, which have been made available to participating investigators, and we have provided collaborating scientists with over 400 custom-synthesized compounds as part of our medicinal chemistry program. Our BSL3 laboratory was independently developed by NERCE using funds provided by Harvard Medical School. The laboratory is registered with the CDC for use of highly regulated select agents and is one of the few in New England open to investigators from our region wishing to work with biodefense pathogens. All collaborating investigators working in the BSL3 undergo a rigorous biosafety training program to ensure safety of laboratory workers and others in the community. The NERCE Biomolecule Production Core has assisted investigators with the production of over 100 different recombinant proteins and carbohydrate preparations;this core has conducted nearly 300 fermentations, resulting in 44 kg of bacterial cell paste. Finally, our proteomics core laboratory has prepared cloned orfeome libraries for both Francisella tularensis and Yersinia pestis, initially in support of New England investigators and subsequently for scientists across the country. Our research program has offered four types of financial support for investigators, including: 1) research projects, 2) developmental projects, 3) career development fellowships, and 4) funding through the RCE "New Opportunities" program. We have funded 17 major research projects, 16 Developmental Projects, 7 Career Development Awards, and 14 additional projects through New Opportunities. Our research has been focused around the themes of host-pathogen interactions and bacterial toxins, themes that we propose to continue over the next five years. We have programs targeted at understanding the mechanisms of innate and adaptive immunity to important pathogens, developing therapeutics and vaccines based on understanding gained from investigating host-pathogen interactions and studying how bacteria and viruses circumvent normal defenses, and understanding how toxins enter and kill host cells. A good example of successful development of a research program that may lead to an important therapeutic intervention is the research program led by James Cunningham, a NERCE investigator based at Brigham and Women's Hospital. Dr. Kartik Chandran, a postdoctoral fellow in the Cunningham lab, was awarded a NERCE Career Development fellowship to support studies of the mechanism by which Ebola virus enters the host cell. This work found that cleavage of the viral glycoprotein by a host protease in the cathepsin family is essential in the early stages of viral entry. Chandran and Cunningham found that the invasive process was interrupted by inhibiting this cleavage with any of a variety of small molecule cathepsin inhibitors. Furthermore, Chandran and Cunningham showed this not only with pseudotyped virus reporter systems, but also with pathogenic Ebola virus as part of a collaboration with scientists from USAMRIID. Dr. Cunningham has more recently begun to focus on a cathepsin inhibitor that is also being studied clinically as a cancer therapeutic. Together with medicinal chemists at the NSRB screening core and animal model specialists affiliated with the BSL3 core, large quantities of the candidate therapeutic have been prepared, and initial bioavailability and dosing studies have been conducted in preparation for challenge studies in guinea pigs and primates. This latter work was supported initially by a NERCE Developmental Projects award and now as a primary research project. The Cunningham project has fulfilled the goals of NERCE in several ways. It began as a basic investigation and advanced to the point where it may be ready for preclinical translational work as part of an effort to identify therapeutics for an infection for which there are no therapies currently available. It also serves as a potential model for how basic discovery could lead to broad-spectrum approaches against multiple agents that invade host cells though similar mechanisms. An example of achieving possible preventive interventions is the work of Dennis Kasper's laboratory on tularemia vaccines. One portion of this project started as a basic study of genes involved in the biosynthesis of the O polysaccharide component of the lipopolysaccharide (LPS) of Francisella tularensis. The important discovery made by the Kasper lab was that the O polysaccharide has a critical role in F. tularensis virulence. Specifically, they found that disruption of an 0 polysaccharide biosynthetic gene (wbtA, a dehydratase) using insertional mutagenesis reduced virulence of the LVS strain of tularensis, with the LD50 in laboratory animals increasing from 101 to 107cfu. The reduction in virulence is attributed to the mutant's increased sensitivity to the bactericidal effects of serum and complement. This observation provoked studies using the attenuated mutant as a potential vaccine to induce cellular immunity against this intracellular pathogen. However, it also became apparent that antibody to O polysaccharide played an important role in protective immunity, leading to additional studies using a combination vaccine of the wbtA mutant plus a glycoconjugate of the O polysaccharide coupled to tetanus toxoid. The results of vaccine / challenge studies in laboratory animals are very encouraging. This combination vaccine is one of the first vaccine candidates shown to be protective against challenge with both wild-type A and B strains of F. tularensis. These F. tularensis vaccine studies could have broad applicability. All gram negative bacteria have LPS, and this approach might be an important model for developing vaccines against other organisms. This project has utilized nearly every core lab in NERCE, including the proteomics core, the small molecule screening core, the biomolecule production core, and the BSL3 core, illustrating that a productive relationship between research scientists and scientists in the core labs can lead to significant scientific accomplishments.